[Adam]

If you gave the ball to the inbounder but possession never changed (either they never passed inbounds or the pass was caught by a teammate of the thrower), line 'em up and shoot.
If the ball was inbounded and possession subsequently changed (steal, made basket, offensive violation, etc.), then you shoot with the lane clear and give the ball to whomever had it at the time you noticed the error.
Note the time limitation on when you can correct this if you did indeed have the ball inbounded.

(edited to remove evidence that I didn't read the OP carefully enough)